Percorrer por autor "Leal, Miguel"
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- Análise longitudinal da performance de jovens futebolistas de formação através de indicadores de carga interna e carga externaPublication . Teixeira, José Eduardo; Forte, Pedro; Leal, Miguel; Silva, A.J.; Barbosa, Tiago M.; Monteiro, A.M.A carga de treino e o estado de recuperação foram avaliados para assegurar níveis adequados de treino nos desportos coletivos. A quantificação da carga de treino pode ser dividida em carga externa e/ou carga interna, fornecendo informações sobre a dose-resposta. A carga externa define o trabalho realizado, independentemente das características internas. Por sua vez, a carga interna revela o stress fisiológico e psicológico. O atual projeto de investigação pretende avaliar os níveis de fadiga e recuperação através de indicadores de carga interna e externa. Trata-se de um design longitudinal (2 anos), avaliando os mesociclos de treino em jogadores de futebol sub-15, sub-17 e sub-19. O follow-up inclui cinco fases de época: (1) pré-época; (2) início da época; (3) metade da época; (4) fim da época; (5) pós-época. Cada mesociclo corresponde a duas semanas e cada semana representa um microciclo. A avaliação da frequência cardíaca (FC) será realizada a intervalos de 5 Hz através de telemetria de curto alcance (Polar RS800cx®). As medidas de carga externa serão obtidas por dispositivos de sistemas de posicionamento global (GPS) de 10 Hz (STATSports Apex®) com acelerómetros tri-axiais integrados de 100Hz. A perceção de esforço será avaliada após cada sessão de treino e jogo, através da escala de perceção do esforço (PSE). A medição da fadiga acumulada será obtida pela Qualidade Total de Recuperação (TQR), antes de cada sessão de treino ou jogo. Os níveis de fadiga serão baseados em: FC de recuperação pós-exercício, variabilidade da FC, rácio HR-RPE e fadiga neuromuscular. A variabilidade da FC será calculada pela diferença entre a FC no final do treino/jogo e a FC registada após 60 segundos de recuperação. Os níveis de fadiga serão avaliados pela variabilidade da FC. No conjunto, pretende-se avaliar a variação das cargas de treino ao longo das diferentes fases da época.
- Effects of chronological age, relative age, and maturation status on accumulated training load and perceived exertion in young sub-elite football playersPublication . Teixeira, José Eduardo; Alves, Ana Ruivo; Ferraz, Ricardo; Forte, Pedro; Leal, Miguel; Ribeiro, Joana; Silva, A.J.; Barbosa, Tiago M.; Monteiro, A.M.The aims of this study were 1) to analyze the influence of chronological age, relative age, and biological maturation on accumulated training load and perceived exertion in young sub-elite football players and 2) to understand the interaction effects amongst age grouping,maturation status, and birth quartiles on accumulated training load and perceived exertion in this target population. A 6-week period (18 training sessions and 324 observation cases) concerning 60 young male sub-elite football players grouped into relative age (Q1 to Q4), age group (U15, U17, and U19), and maturation status (Pre-peak height velocity (PHV), Mid-PHV, and Post- PHV) was established. External training load data were collected using 18 Hz global positioning system technology (GPS), heart-rate measures by a 1 Hz short-range telemetry system, and perceived exertion with total quality recovery (TQR) and rating of perceived exertion (RPE). U17 players and U15 players were 2.35 (95% CI: 1.25–4.51) and 1.60 (95% CI: 0.19–4.33) times more likely to pertain to Q1 and Q3, respectively. A negative magnitude for odds ratio was found in all four quartile comparisons within maturation status (95% CI: 6.72–0.64), except for Mid-PHV on Q2 (95% CI: 0.19–4.33). Between- and within-subject analysis reported significant differences in all variables on age group comparison measures (F = 0.439 to 26.636, p = 0.000 to 0.019, η2 = 0.003–0.037), except for dynamic stress load (DSL). Between-subject analysis onmaturity status comparison demonstrated significant differences for all training load measures (F = 6.593 to 14.424, p = 0.000 to 0.037, η2 = 0.020–0.092). Interaction effects were found for age group xmaturity band x relative age (Λ Pillai’s = 0.391, Λ Wilk’s = 0.609, F = 11.385, p = 0.000, η2 = 0.391) and maturity band x relative age (Λ Pillai’s = 0.252, Λ Wilk’s = 0.769,F=0.955, p = 0.004, η2 = 0.112). Current research has confirmed the effects of chronological age, relative age, and biological maturation on accumulated training load. Perceived exertion does not seem to show any differences concerning age group or maturity status. Evidence should be helpful for professionals to optimize the training process and young football players’ performance.
- Effects of match location, quality of opposition and match outcome on match running performance in a portuguese professional football teamPublication . Teixeira, José Eduardo; Leal, Miguel; Ferraz, Ricardo; Ribeiro, Joana; Cachada, José M.; Barbosa, Tiago M.; Monteiro, A.M.; Forte, PedroThe aim of this study was to analyze the effects of match location, quality of opposition and match outcome on match running performance according to playing position in a Portuguese professional football team. Twenty-three male professional football players were monitored from eighteen Portuguese Football League matches during the 2019–2020 season. Global positioning system technology (GPS) was used to collect time-motion data. The match running performance was obtained from five playing positions: central defenders (CD), fullbacks (FB), central midfielders (CM), wide midfielders (WM) and forwards (FW). Match running performance was analyzed within specific position and contextual factors using one-way analysis of variance (ANOVA) for repeated measures, standardized (Cohen) differences and smallest worthwhile change. CM and WM players covered significantly greater total distance (F = 15.45, p = 0.000, 2 = 0.334) and average speed (F = 12.79, p < 0.001, 2 = 0.294). WM and FB players covered higher distances at high-speed running (F = 16.93, p = 0.000, 2 = 0.355) and sprinting (F = 13.49; p < 0.001, 2 = 0.305). WM players covered the highest number of accelerations (F = 4.69, p < 0.001, 2 = 0.132) and decelerations (F = 12.21, p < 0.001, 2 = 0.284). The match running performance was influenced by match location (d = 0.06–2.04; CI: 0.42–2.31; SWC = 0.01–1.10), quality of opposition (d = 0.13–2.14; CI: –0.02–2.60; SWC = 0.01–1.55) and match outcome (d = 0.01–2.49; CI: 0.01–2.31; SWC = 0.01–0.35). Contextual factors influenced the match running performance with differential effects between playing positions. This study provides the first report about the contextual influence on match running performance in a Portuguese professional football team. Future research should also integrate tactical and technical key indicators when analyzing the match-related contextual influence on match running performance.
- Effects of match location, quality of opposition and match outcome on match running performance in a Portuguese professional football teamPublication . Teixeira, José Eduardo; Leal, Miguel; Ferraz, Ricardo; Ribeiro, Joana; Cachada, José M.; Barbosa, Tiago M.; Monteiro, A.M.; Forte, PedroThe aim of this study was to analyze the effects of match location, quality of opposition and match outcome on match running performance according to playing position in a Portuguese professional football team. Twenty-three male professional football players were monitored from eighteen Portuguese Football League matches during the 2019–2020 season. Global positioning system technology (GPS) was used to collect time-motion data. The match running performance was obtained from five playing positions: central defenders (CD), fullbacks (FB), central midfielders (CM), wide midfielders (WM) and forwards (FW). Match running performance was analyzed within specific position and contextual factors using one-way analysis of variance (ANOVA) for repeated measures, standardized (Cohen) differences and smallest worthwhile change. CM and WM players covered significantly greater total distance (F = 15.45, p = 0.000, η2 = 0.334) and average speed (F = 12.79, p < 0.001, η2 = 0.294). WM and FB players covered higher distances at high-speed running (F = 16.93, p = 0.000, η2 = 0.355) and sprinting (F = 13.49; p < 0.001, η2 = 0.305). WM players covered the highest number of accelerations (F = 4.69, p < 0.001, η2 = 0.132) and decelerations (F = 12.21, p < 0.001, η2 = 0.284). The match running performance was influenced by match location (d = 0.06–2.04; CI: −0.42–2.31; SWC = 0.01–1.10), quality of opposition (d = 0.13–2.14; CI: –0.02–2.60; SWC = 0.01–1.55) and match outcome (d = 0.01–2.49; CI: −0.01–2.31; SWC = 0.01–0.35). Contextual factors influenced the match running performance with differential effects between playing positions. This study provides the first report about the contextual influence on match running performance in a Portuguese professional football team. Future research should also integrate tactical and technical key indicators when analyzing the match-related contextual influence on match running performance
- Longitudinal assessment of physical performance in soccer players by internal and external loadPublication . Teixeira, José Eduardo; Forte, Pedro; Leal, Miguel; Silva, A.J.; Barbosa, Tiago M.; Monteiro, A.M.The training load and recovery status has been assessed to ensure appropriate training and intensity levels in team sports. The training load quantifications can be breakdown in external load and/or internal load, providing insights about the dose-response. The external load is defined as the performed work, such as speed and covered distance, regardless the internal characteristics. Otherwise, the internal load reveals the training physiological and psychological stress. The current research project intends to assess fatigue and recovery levels by internal and external load. This is a longitudinal design (2 years), following-up the training mesocycles in U-15, U-17 and U-19 football players. The evaluation includes five season phases: (1) pre-season (or baseline); (2) beginning of the season (in-season or mid-phase); (3) half of the mid-phase; (4) end of mid-phase; (5) post-season. Each mesocycle corresponds to two weeks and each week represents a microcycle. Heart rate (HR) assess will be performed at 5 Hz intervals using short-range radio telemetry (Polar RS800cx®). The external load measures will be obtained by the global 10 Hz global positioning systems (GPS) devices (STATSports Apex®) with 100Hz tri-axial accelerometers. The perceived exertion will be evaluated after each training session and match-play, through the rating of perceived exertion (RPE) scale. The measurement of accumulated fatigue will be obtained by Total Quality of Recovery (TQR) scale, before each training session or match-play. The fatigue levels will be based on: postexercise recovery heart rate (HRR), heart rate variability (HRV), HR-RPE ratio and neuromuscular fatigue. HRR will be calculated by the difference between HR at the end of training/match-play and the registered HR after 60 seconds of recovery. The fatigue levels will be assessed by the HR variability. Altogether, it is intended to assess the training loads variation between trainings and intra-training (exercise and training phases) over the different season phases.
- Match-to-Match Variation on High-Intensity Demands in a Portuguese Professional Football TeamPublication . Teixeira, José Eduardo; Branquinho, Luís; Leal, Miguel; Morgans, Ryland; Sortwell, Andrew; Barbosa, Tiago M.; Monteiro, A.M.; Afonso, Pedro; Machado, Guilherme; Encarnação, Samuel; Ferraz, Ricardo; Forte, PedroThe aim of this study was to analyze the match-to-match variation in high-intensity demands from one Portuguese professional football team according to playing positions. Twentythree male outfield professional football players were observed during eighteen matches of the Portuguese Second League. Time–motion data were collected using Global Positioning System (GPS) technology. Match running performance was analyzed based on the following three playing positions: defenders (DF), midfielders (MF), and forwards (FW). Repeated measures ANOVA was utilized to compare match running performance within each position role, and seasonal running variation. Practical differences were assessed using the smallest worthwhile change (SWC), coefficient of variation (CV), and twice the coefficient of variation (2CV). Significant differences were found among playing positions in total distance covered (F = 15.45, p < 0.001, η2 = 0.33), average speed (F = 12.79, p < 0.001, η2 = 0.29), high-speed running (F = 16.93, p < 0.001, η2 = 0.36), sprinting (F = 13.49, p < 0.001, η2 = 0.31), accelerations (F = 4.69, p = 0.001, η2 = 0.132), and decelerations (F = 12.21, p < 0.001, η2 = 0.284). The match-to-match running performance encompassed TD (6.59%), AvS (8.67%), HSRr (37.83%), SPR (34.82%), ACC (26.92%), and DEC (27.85%). CV values for total distance covered ranged from 4.87–6.82%, with forwards and midfielders exhibiting the greatest and smallest variation, respectively. Midfielders demonstrated the highest match-to-match variation for all other analyzed variables (8.12–69.17%). All playing positions showed significant variation in high-demanding variables (26.94–37.83%). This study presents the initial analysis of match-tomatch variation in high-intensity demands within a Portuguese professional football team. Thus, the position’s specificity and context can provide a helpful strategy for evaluating match-to-match running performance, and for recommending individualized training exercises based on the peak and high-intensity demands for each player’s role within the game.
- Measuring power, force, velocity, and mechanical effectiveness in Football: theoretical considerationsPublication . Teixeira, José Eduardo; Forte, Pedro; Ferraz, Ricardo; Branquinho, Luís; Leal, Miguel; Ribeiro, Joana; Monteiro, A.M.; Barbosa, Tiago M.Power-force-velocity profiles in football can be assessed by Samozino’s formulas to determine theoretical maximal velocity (V0), theoretical horizontal force (F0), horizontal power (Pmax) and force-velocity (F-V) profile (i.e., the slope of the F-V relationship; Sfv), ratio of force (RFmax) and index of force application technique (DRF). Current critical review aims to explain the theoretical and methodological procedures for measuring power, force, velocity, and mechanical effectiveness in Football. In conclusion, Samozino’s method is sensitive, straightforward, and cost-effective for measuring F-V relationship and mechanical effectiveness in Football. Therefore, this methodological approach should be considered in field-based assessment and monitoring strategy of the football players. Future research should also include different competitive level such as elite, sub-elite and recreational for measuring power, force, velocity, and mechanical effectiveness in male, female, and youth football environments.
- Modeling the major influencing factor on match running performance during the in-season phase in a Portuguese professional football teamPublication . Teixeira, José Eduardo; Branquinho, Luís; Leal, Miguel; Marinho, D.A.; Ferraz, Ricardo; Barbosa, Tiago M.; Monteiro, A.M.; Forte, PedroThe aim of this study was two-fold: (1) to analyze the influence of season phase (i.e., the start of the in-season and mid-in-season) on match running performance in a Portuguese professional football team; (2) to determine and model the main factor influencing match running performance during the in-season in this specific football team. Eighteen matches were collected by an 18 Hz global positioning system (GPS) from a professional Portuguese football team during the start of the in-season and mid-in-season. The match running performance was analyzed according to season phases, presenting significant differences in total distance (TD) (tlower bound = 4.71, p < 0.001; tupper bound = −2.22, p = 0.002), average speed (AvS) (tlower bound = 359.45, p < 0.001; tupper bound = −359.87, p < 0.001), and relative high speed running (rHSR) (tlower bound = 13.10, p < 0.001; tupper bound = −10.21, p < 0.001). The logistic regression showed TD (β = −1.59, z = −2.84, p = 0.005) and AvS (β = 2.68, z = −2.84, p = 0.007) as the major factors influencing match running performance during seasonal variation. Sprints and accelerations showed no significance for predicting match running performance during the season phases (β = −0.05 to 1.07, z = −0.95 to 1.07, p = 0.29 to 0.72). Current research confirms that lower and upper bounds should be used to quantify seasonal differences on match running performance. TD and AvS were described as the main factors influencing match running performance during the in-season phase. Thus, it is important to highlight the pace and volume of the game to maximize match running performance.
- Monitoring accumulated training and match load in football: a systematic reviewPublication . Teixeira, José Eduardo; Forte, Pedro; Ferraz, Ricardo; Leal, Miguel; Ribeiro, Joana; Silva, A.J.; Barbosa, Tiago M.; Monteiro, A.M.Training load monitoring has become a relevant research-practice gap to control training and match demands in team sports. However, there are no systematic reviews about accumulated training and match load in football. (2) Methods: Following the preferred reporting item for systematic reviews and meta-analyses (PRISMA), a systematic search of relevant Englishlanguage articles was performed from earliest record to March 2020. The search included descriptors relevant to football, training load, and periodization. (3) Results: The literature search returned 7972 articles (WoS = 1204; Pub-Med = 869, SCOPUS = 5083, and SportDiscus = 816). After screening, 36 full-text articles met the inclusion criteria and were reviewed. Eleven of the included articles analyzed weekly training load distribution; fourteen, the weekly training load and match load distribution; and eleven were about internal and external load relationships during training. The reviewed articles were based on short-telemetry systems (n = 12), global positioning tracking systems (n = 25), local position measurement systems (n = 3), and multiple-camera systems (n = 3). External load measures were quantified with distance and covered distance in different speed zones (n = 27), acceleration and deceleration (n = 13) thresholds, accelerometer metrics (n = 11), metabolic power output (n = 4), and ratios/scores (n = 6). Additionally, the internal load measures were reported with perceived exertion (n = 16); heart-rate-based measures were reported in twelve studies (n = 12). (4) Conclusions: The weekly microcycle presented a high loading variation and a limited variation across a competitive season. The magnitude of loading variation seems to be influenced by the type of week, player’s starting status, playing positions, age group, training mode and contextual variables. The literature has focused mainly on professional men; future research should be on the youth and female accumulated training/match load monitoring.
- Quantifying sub-elite youth football weekly training load and recovery variationPublication . Teixeira, José Eduardo; Forte, Pedro; Ferraz, Ricardo; Leal, Miguel; Ribeiro, Joana; Silva, A.J.; Barbosa, Tiago M.; Monteiro, A.M.Monitoring the training load in football is an important strategy to improve athletic performance and an effective training periodization. The aim of this study was two-fold: (1) to quantify the weekly training load and recovery status variations performed by under-15, under-17 and under-19 sub-elite young football players; and (2) to analyze the influence of age, training day, weekly microcycle, training and playing position on the training load and recovery status. Twenty under-15, twenty under-17 and twenty under-19 players were monitored over a 2-week period during the first month of the 2019-2020 competitive season. Global positioning system technology (GPS) was used to collect external training loads: total distance covered, average speed, maximal running speed, relative high-speed running distance, high metabolic load distance, sprinting distance, dynamic stress load, accelerations and decelerations. Internal training load was monitored using ratings of perceived exertion (RPE) and session rating of perceived exertion (sRPE). Recovery status was obtained using the total quality recovery (TQR) scale. The results show an age-related influence for external training load (p <= 0.001; d = 0.29-0.86; moderate to strong effect), internal training load (p <= 0.001, d = 0.12-0.69; minimum to strong effect) and recovery status (p <= 0.001, d = 0.59; strong effect). The external training load presented differences between training days (p < 0.05, d = 0.26-0.95; moderate to strong effect). The playing position had a minimum effect on the weekly training load (p < 0.05; d = 0.06-0.18). The weekly microcycle had a moderate effect in the TD (p < 0.05, d = 0.39), RPE (p < 0.05; d = 0.35) and sRPE (p < 0.05, d = 0.35). Interaction effects were found between the four factors analyzed for deceleration (F = 2.819, p = 0.017) and between inter-day, inter-week and age for total covered distance (F = 8.342, p = 0.008). This study provided specific insights about sub-elite youth football training load and recovery status to monitor training environments and load variations. Future research should include a longer monitoring period to assess training load and recovery variations across different season phases.